A video signal of video captured by a video camera is transmitted to a switcher via a transmission cable. Because it is difficult to transmit an electric signal without attenuation when the devices are positioned remote from the video camera, a camera adaptor provided to the video camera converts the electric signal into an optical signal, and transmits the converted optical signal via an optical transmission cable. Then, a base station provided to the remotely-located device converts the optical signal into the electric signal. As above, long distance transmission is conducted. The long distance transmission is usually bidirectional, and signals of video (hereinafter referred to as “return video”) employed by the switcher are optically transmitted from the base station side to the camera adaptor.
A broadcast video camera in general receives a return video signal from the switcher and has a function to switch video display of the view finder between currently captured video (hereinafter referred to as “camera video”) and the return video from the switcher when the operator of the camera presses a return button of the lens mounted on the video camera or presses a return button of a zoom remote controller attached to the lens mounted on the video camera.
Recently, video camera performance has been improved, and therefore this has made it possible to capture video of quality high enough for broadcasting by using a less expensive video camera without using a very expensive video camera designed for broadcast use. Although the less expensive camera is capable of providing high quality video, the camera fails to receive the return video by a main body thereof because the camera is not designed with consideration of broadcast use. Thus, it has not been possible to use the less expensive video camera for broadcasting even though the video camera provides sufficient quality video.
Under the above circumstance, Patent Document 1 discloses a view finder capable of switching between the camera video and the return video, as a view finder capable of employing a less expensive video camera for broadcasting.